Re: Oscillation Drives

::: reaction mass. It is simply being caught and recycled.

:: Yes, that does cancel out the thrust, completely. Actually it's not
:: in the first place the process of "drawing it back", but the part
:: where you catch it. The "catching glove" must be somehow connected
:: to the ship, and the reaction mass hitting the "glove" at its speed
:: will create an equal impulse in the opposite direction. Even if it
:: were magnetic fields (instead of real matter) catching a charged
:: particle stream it would still be force against force, providing an
:: acceleration of zero. So rest assured that there is really now way
:: around it unless you want to throw known physics overboard.

: boomertiro@xxxxxxxxx
: Awesome, I like where this is going.
: What about the time in between the throw and the catch. Wouldn't
: there be positive momentum until the catch, than the stop?

Shrug. Or simply note that if the spacecraft isn't throwing anything
away, it's a closed systemm, so conservation of momentum requires it
just sit there. Going into rube-goldberg-esque details about just
how the momentum gets cancelled is barking up the wrong misdirection;
the ship plus the masses it's throwing around internally can't gain
(or lose) any momentum, period.

I know you said

I clearly understand the concepts of conservation
of momentum and energy.

but it seems more like you clearly don't, or at least aren't
looking at your problem from a reasonable perspective.
Sort of missing the whole-spaceship forest by concentrating
on the reaction-mass trees.

But yes, if you move a mass from the nose to the tail of the ship,
and then stop it, the outside of the ship will move forward, then stop.
And when you move it back to the nose, the ship will move back to where
it was before. Because its center of mass isn't going to go anywhere.

Of course, the next question is most often "but what if it's moved
very very fast from nose to tail, and then slooooooooooowly bright back
to the nose, couldn't you inchworm along? And the answer is, no,
you can't. Slow or fast makes no difference, the center of mass
of the ship cannot be displaced when the mass is back where it
started, or momentum isn't being conserved.

So. Why do our intuitions say this sort of thing can work, and indeed,
you can "scoot" along the floor, and off-balance washing machines can
"walk" around during the spin cycle? Simple. Friction. Extra momentum
is being exchanged with the floor via friction. If there were something
akin to a floor upon which your ship rests, or a fluid in which your
ship floats, in space, it could be made to work there too, but there
really isn't.

Or, put another way, because of friction being ubiquitous in the
environment we're adapted to, our intuitions are programmed with
aristotelean physics, not newtonian. The universe, however,
doesn't seem to care about our intuitions.


Wayne Throop throopw@xxxxxxxxx http://sheol.org/throopw
.

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